What happens when American Express uses Twitter to promote a discount coupon?

Try around four or five retweets a minute.

American Express launched Amex Sync last February to tap into the Twitter audience by offering promotional discounts in exchange for retweets. In other words, if Twitter users who sync with American Express — in other words, give Amex access to their Twitter accounts — retweet discount offers, the users get the discount.

Just before 9 am ET today, for example, Amex tweeted the following offer on its main Twitter feed:

Tweet #AmexLowes, get $10 back 1x on $50+ in-store/online purchs at Lowe’s w/synced Amex Card! RegLtd Exp 11/15Terms:http://t.co/GAox9cQ7tp

— American Express (@AmericanExpress) October 8, 2013

Those Twitter users who sign up for Amex Sync can retweet that Lowe’s offer and score $10 back on their next $50 purchase with the store. The key is retweeting the offer.

This Lowe’s offer generated an average of four or five retweets per minute in the hour after it was first posted, by our rough estimate. Twitter users like Jenise, Alexis Forbes, and Debbie Leonardo all retweeting the Lowe’s offer within the first hour. Twitter users who retweet offers — most of whom appear to be women — are already signed up with Amex Sync.

In addition to Lowe’s, Amex has run Sync offers for Victorinox, Dell, and Rebecca Minkoff, a fashion label.

Are the four or five RTs per minute worth American Express and Lowe’s efforts? That’s for Amex and Lowe’s to determine.